Question 1

A β+ particle is also known as

Accepted Answer

A)  an electron. 
B)  a positron. 
C)  a helium nucleus. 
D)  a high-energy photon. 
A)  an electron. 
B)  a positron. 
C)  a helium nucleus. 
D)  a high-energy photon.

Question 2

In the fission reaction 235U + 1n → 141Ba + 92Kr + x 1n, what is the number x of neutrons produced?

Accepted Answer

A)  0 
B)  1 
C)  2 
D)  3 
A)  0 
B)  1 
C)  2 
D)  3

Question 3

A β- decay occurs in an unstable nucleus when

Accepted Answer

A)  a proton is converted to an electron by the strong force. 
B)  a proton is converted to a neutron by the strong force. 
C)  a neutron is converted to a proton by the weak force. 
D)  a neutron is converted to an alpha particle by the weak force. 
E)  a neutron is converted to a positron by the weak force. 
A)  a proton is converted to an electron by the strong force. 
B)  a proton is converted to a neutron by the strong force. 
C)  a neutron is converted to a proton by the weak force. 
D)  a neutron is converted to an alpha particle by the weak force. 
E)  a neutron is converted to a positron by the weak force.

Question 4

Consider the nuclear reaction $
^{14}
_{7}
N + ^{4}
_{2}
 He → ^{17}
_{8}
 O + 
^{1} 
_{1}
 H$. The known atomic masses are $
^{14} 
_{7}
 N: 14.003074\ u\ ^{4}
_{2}
 He: 4.002603\ u\ 
^{1} 
_{1}
 H: 1.007825 u\ ^{17}

_{8}
 O: 16.999131 u$ What is the Q-value (or reaction energy) of this reaction? (1 u = 931.5 MeV/c2)

Accepted Answer

A)  -1.191 MeV 
B)  -2.020 MeV 
C)  -6.725 MeV 
D)  -9.055 MeV 
A)  -1.191 MeV 
B)  -2.020 MeV 
C)  -6.725 MeV 
D)  -9.055 MeV

Question 5

If a 2.0-MeV neutron released in a fission reaction loses half its kinetic energy in each moderator collision, how many collisions are needed to reduce its kinetic energy to 1/25 eV?

Accepted Answer

A)  6 
B)  18 
C)  26 
D)  30 
E)  4 
A)  6 
B)  18 
C)  26 
D)  30 
E)  4

Question 6

If a Σ- particle at rest decays into a neutron and a π- , what is the total kinetic energy of the decay products? The masses of Σ-, neutron, and π- are 1197 MeV/c2, 940 MeV/c2, and 140 MeV/c2, respectively.

Accepted Answer

Question 7

One material used in nuclear bombs is 239Pu, with a half-life of 24,000 years. How long must we wait for a buried stockpile of this substance to decay to 1/1000 of its original activity?

Accepted Answer

A)  1,200,000 years 
B)  240,000 years 
C)  150,000 years 
D)  82,000 years 
E)  1,500 years 
A)  1,200,000 years 
B)  240,000 years 
C)  150,000 years 
D)  82,000 years 
E)  1,500 years

Question 8

What are the possible charges of a quark (not an antiquark)?

Accepted Answer

A)  -e, 0, e 
B)  -2/3 e, -1/3 e, +1/3 e, +2/3 e 
C)  -2/3 e, +1/3 e 
D)  -1/3 e, +2/3 e 
E)  -1/3 e, +1/3 e 
A)  -e, 0, e 
B)  -2/3 e, -1/3 e, +1/3 e, +2/3 e 
C)  -2/3 e, +1/3 e 
D)  -1/3 e, +2/3 e 
E)  -1/3 e, +1/3 e

Question 9

The stability of $
^{11} _{6}
C $ with respect to alpha, beta-plus and beta-minus decay is to be determined. The following atomic masses are known: $
^{4}
_{2}
$ He: 4.002603 u $
^{7}
_{4}
$ Be: 7.016928 u $ ^{11} 
_{5}$ B: 11.009305 u $
^{11} 
_{6}
$ C: 11.011433 u $
^{11} 
_{7} $ N: 11.026742 u The $
^{11} 
_{6}
$ C nucleus is

Accepted Answer

A)  not subject to alpha, beta-plus or beta-minus decay. 
B)  subject to alpha decay only. 
C)  subject to beta-plus decay only. 
D)  subject to beta-minus decay only. 
E)  subject to beta-plus or beta-minus decay, but not to alpha decay. 
A)  not subject to alpha, beta-plus or beta-minus decay. 
B)  subject to alpha decay only. 
C)  subject to beta-plus decay only. 
D)  subject to beta-minus decay only. 
E)  subject to beta-plus or beta-minus decay, but not to alpha decay.

Question 10

When a neutron collides with a uranium-235 nucleus it can induce a variety of fission reactions. One such reaction is$^{235}_{92}$U + $^{1}_{0}$ n → $^{140}_{54}$ Xe + $^{94}_{38}$ Sr + 2 $^{1}_{0}$n The following mass values are known: $^{140}_{54}$ Xe: 139.921620 u $^{94}_{38}$Sr: 93.915367 u $^{235}_{92}$ U: 235.043924 u $^{1}_{0}$ n: 1.008665 u What mass of uranium is needed to produce a 10-kiloton yield?
(1 u = 931.5 MeV/c2 = 1.66054 × 10-27 kg, 1-kiloton yield = 5.0 × 1012 J)

Accepted Answer

A)  0.57 kg 
B)  0.66 kg 
C)  6.58 kg 
D)  3.85 kg 
E)  1.10 kg 
A)  0.57 kg 
B)  0.66 kg 
C)  6.58 kg 
D)  3.85 kg 
E)  1.10 kg

Question 11

A thallium source with a half-life of 3.7 years was certified at 10 kBq ten years ago. What is its activity now?

Accepted Answer

A)  4.7 kBq 
B)  3.3 kBq 
C)  1.5 kBq 
D)  1.0 kBq 
A)  4.7 kBq 
B)  3.3 kBq 
C)  1.5 kBq 
D)  1.0 kBq

Question 12

Fermium-253 has a half-life of 3.00 days. A sample of fermium has 3.88 × 106 nuclei. What is the initial activity of this sample?

Accepted Answer

A)  10.4 Bq 
B)  10.4 kBq 
C)  12.9 Bq 
D)  12.9 kBq 
A)  10.4 Bq 
B)  10.4 kBq 
C)  12.9 Bq 
D)  12.9 kBq

Question 13

The following masses are known: 
$^{1}_{0}$n 1.008665 u $^{1}_{1}$ H 1.007825 u $^{226}_{88}$Ra 226.025403 u What is the binding energy of $^{226}_{88}$Ra? 
(1 u = 931.5MeV/c2)

Accepted Answer

A)  1700 MeV 
B)  1900 MeV 
C)  2100 MeV 
D)  2300 MeV 
E)  2500 MeV 
A)  1700 MeV 
B)  1900 MeV 
C)  2100 MeV 
D)  2300 MeV 
E)  2500 MeV

Question 14

An excited $^{236}_{92}$ U* nucleus undergoes fission into two fragments as follows: $^{236}_{92}$U*→ $^{144}_{56}$ Ba + $^{92}_{36}$ Kr The following atomic masses are known:$^{92}_{36}$Kr: 91.926270 u $^{144}_{56}$Ba: 143.922845 u $^{236}_{92}$ U*: 236.045563 u
What is the reaction energy released during this fission reaction? 
(1 u = 931.5 MeV/c2)

Accepted Answer

A)  150 MeV 
B)  160 MeV 
C)  170 MeV 
D)  180 MeV 
E)  190 MeV 
A)  150 MeV 
B)  160 MeV 
C)  170 MeV 
D)  180 MeV 
E)  190 MeV

Question 15

Today, uranium contains $0.72 \%$ $235 \mathrm { U }$ (half-life = 0.70 billion years) and $99.28 \%$ ${ } ^ { 238 } \mathrm { U }$ (half-life = 4.5 billion years). At a time 1.9 billion years ago, what was the fraction of $235 \mathrm { U }$ in uranium?

Accepted Answer

A)  3.53% 
B)  4.72% 
C)  4.90% 
D)  6.76% 
A)  3.53% 
B)  4.72% 
C)  4.90% 
D)  6.76%

Question 16

What are the mass number A and the charge (in units of e) for each of the following particles or rays?
(a) beta-plus
(b) beta-minus
(c) gamma ray

Accepted Answer

(a) 0, 1 (

Question 17

Two radioactive isotopes, X and Y, both decay to stable products. The half-life of X is about a day, while that of Y is about a week. Suppose a radioactive sample consists of a mixture of these two nuclides. If the mixture is such that the activities arising from X and Y are initially equal, then a few days later the activity of the sample will be due

Accepted Answer

A)  predominantly to Y. 
B)  predominantly to X. 
C)  entirely to Y. 
D)  to X and Y equally. 
A)  predominantly to Y. 
B)  predominantly to X. 
C)  entirely to Y. 
D)  to X and Y equally.

Question 18

A radioactive source emits 2.4-MeV neutrons at the rate of 7100 neutrons per second. The number of atoms in the source is $2.6 \times 10 ^ { 9 }$ What is the activity of the source, in curies (Ci)? (1.00 Ci = 3.70 × 1010 Bq)

Accepted Answer

A)  190 nCi 
B)  1900 nCi 
C)  19 nCi 
D)  71 nCi 
E)  710 nCi 
A)  190 nCi 
B)  1900 nCi 
C)  19 nCi 
D)  71 nCi 
E)  710 nCi

Question 19

Suppose that starting with $^{227}_{89}$ , the following sequence of decays occurs: first an alpha decay, then a beta-minus decay, and finally another alpha decay. What isotope is left after each one of the decays?

Accepted Answer

None

Question 20

A nuclear explosion results in a mass decrease of $2.10 \mathrm {~g}$ How much energy is released during this explosion? (c = 3.00 × 108 m/s)

Accepted Answer

A)  1.89 × 1014 J 
B)  6.30 × 105 J 
C)  1.89 × 1013 J 
D)  2.25 × 1012 J 
A)  1.89 × 1014 J 
B)  6.30 × 105 J 
C)  1.89 × 1013 J 
D)  2.25 × 1012 J

Exam 30: Nuclear Physics

A β+ particle is also known as

In the fission reaction 235U + 1n → 141Ba + 92Kr + x 1n, what is the number x of neutrons produced?

A β- decay occurs in an unstable nucleus when

If a 2.0-MeV neutron released in a fission reaction loses half its kinetic energy in each moderator collision, how many collisions are needed to reduce its kinetic energy to 1/25 eV?

If a Σ- particle at rest decays into a neutron and a π- , what is the total kinetic energy of the decay products? The masses of Σ-, neutron, and π- are 1197 MeV/c2, 940 MeV/c2, and 140 MeV/c2, respectively.

One material used in nuclear bombs is 239Pu, with a half-life of 24,000 years. How long must we wait for a buried stockpile of this substance to decay to 1/1000 of its original activity?

What are the possible charges of a quark (not an antiquark)?

A thallium source with a half-life of 3.7 years was certified at 10 kBq ten years ago. What is its activity now?

Fermium-253 has a half-life of 3.00 days. A sample of fermium has 3.88 × 106 nuclei. What is the initial activity of this sample?

The following masses are known: 01^{1}_{0}01​ n 1.008665 u 11^{1}_{1}11​ H 1.007825 u 88226^{226}_{88}88226​ Ra 226.025403 u What is the binding energy of 88226^{226}_{88}88226​ Ra? (1 u = 931.5MeV/c2)

Today, uranium contains 0.72%0.72 \%0.72% 235U235 \mathrm { U }235U (half-life = 0.70 billion years) and 99.28%99.28 \%99.28% 238U{ } ^ { 238 } \mathrm { U }238U (half-life = 4.5 billion years). At a time 1.9 billion years ago, what was the fraction of 235U235 \mathrm { U }235U in uranium?

What are the mass number A and the charge (in units of e) for each of the following particles or rays? (a) beta-plus (b) beta-minus (c) gamma ray

A radioactive source emits 2.4-MeV neutrons at the rate of 7100 neutrons per second. The number of atoms in the source is 2.6×1092.6 \times 10 ^ { 9 }2.6×109 What is the activity of the source, in curies (Ci)? (1.00 Ci = 3.70 × 1010 Bq)

Suppose that starting with 89227^{227}_{89}89227​ , the following sequence of decays occurs: first an alpha decay, then a beta-minus decay, and finally another alpha decay. What isotope is left after each one of the decays?

A nuclear explosion results in a mass decrease of 2.10 g2.10 \mathrm {~g}2.10 g How much energy is released during this explosion? (c = 3.00 × 108 m/s)

Representing Motion

Motion in One Dimension

Vectors and Motion in Two Dimensions

Forces and Newtons Laws of Motion

Applying Newtons Laws

Gravity

Rotational Motion

Equilibrium Ad Elasticity

Momentum

Energy and Work

Using Energy

Thermal Properties of Matter

Fluids

Oscillations

Traveling Waves and Sound

Superposition and Standing Waves

Wave Optics

Ray Optics

Optical Instruments

Electric Fields and Forces

Electric Potential

Current and Resistance

Circuits

Magnetic Fields and Forces

EM Induction and Em Waves

AC Electricity

Relativity

Quantum Physics

Atoms and Molecules

Filters

A β⁺particle is also known as

In the fission reaction ²³⁵U + ¹n → ¹⁴¹Ba + ⁹²Kr + x ¹n, what is the number x of neutrons produced?

A β^- decay occurs in an unstable nucleus when

If a Σ^- particle at rest decays into a neutron and a π^- , what is the total kinetic energy of the decay products? The masses of Σ^-, neutron, and π^- are 1197 MeV/c², 940 MeV/c², and 140 MeV/c², respectively.

One material used in nuclear bombs is ²³⁹Pu, with a half-life of 24,000 years. How long must we wait for a buried stockpile of this substance to decay to 1/1000 of its original activity?

Fermium-253 has a half-life of 3.00 days. A sample of fermium has 3.88 × 10⁶ nuclei. What is the initial activity of this sample?

The following masses are known: $^{1}_{0}$ n 1.008665 u $^{1}_{1}$ H 1.007825 u $^{226}_{88}$ Ra 226.025403 u What is the binding energy of $^{226}_{88}$ Ra? (1 u = 931.5MeV/c²)

Today, uranium contains $0.72 \%$ $235 \mathrm { U }$ (half-life = 0.70 billion years) and $99.28 \%$ ${ } ^ { 238 } \mathrm { U }$ (half-life = 4.5 billion years). At a time 1.9 billion years ago, what was the fraction of $235 \mathrm { U }$ in uranium?

A radioactive source emits 2.4-MeV neutrons at the rate of 7100 neutrons per second. The number of atoms in the source is $2.6 \times 10 ^ { 9 }$ What is the activity of the source, in curies (Ci)? (1.00 Ci = 3.70 × 10¹⁰ Bq)

Suppose that starting with $^{227}_{89}$ , the following sequence of decays occurs: first an alpha decay, then a beta-minus decay, and finally another alpha decay. What isotope is left after each one of the decays?

A nuclear explosion results in a mass decrease of $2.10 \mathrm {~g}$ How much energy is released during this explosion? (c = 3.00 × 10⁸ m/s)